Btrfs, RAID, iSCSI questions

[BlueFusion]

Hey folks,

I've been using Btrfs for some time now and have had great success. My current desktop is a i7-940 with 24GB RAM and a bunch of drives in a Btrfs JBOD array on top of dm-crypt. I don't want to upgrade this until Sky Lake processors are available but I want to increase drive throughput with AES-NI. I was thinking of building a small Haswell server and using iSCSI.

I'm going to bond dual gigabit ports on each machine for a theoretical throughput of around 250MB/sec. Right now my CPU will give me a max of ~135MB/sec sustained throughput because of the AES encryption maxing out a core (and it only ever uses one core even though it's multi-threaded).

I'm starting with 6 drives and will be adding from there.

What's the ideal way to go about doing this? Or maybe it's just a bad idea in general.

What I was thinking...

I can map each of the encrypted disks on the Haswell server, and make each of those iSCSI targets. My desktop will have to initiate each of the mapped drives in iSCSI and then use Btrfs RAID 5 (or whatever option I choose).

Alternatively, would it be better to install a RAID card in the server, create two RAID 0 arrays an creating two iSCSI targets so my desktop only has to initiate two iSCSI targets and use Btrfs RAID1 on my desktop? In theory, this would give me, in essence, RAID 10 with data checksums, right?
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i7-940 2.93Ghz | ASUS P6T Deluxe (v.1) | 24GB Triple Channel RAM | nVidia GTX660
4x 4TB Seagate NAS HDD (Btrfs raid5) | 2x 120GB Samsung 850 EVO SSD (Btrfs raid1)